This invention relates to the processing of audio signals and, more particularly, to an apparatus and method for dynamically adjusting the amplitude of an audio signal.
It is well known that when a portion of an electronic audio signal received by a circuit or system momentarily exceeds the amplitude processing capability of the circuit or system, the result will be a distortion of the sound in the ultimately reproduced audio. Typically, when the audio signal is amplified, portions thereof which exceed the amplitude range of the amplifier will be clipped, and the consequence is an undersirable distortion.
A number of techniques are conventionally employed for adjusting the average amplitude or the peak amplitude of a received audio signal to prevent clipping or other distortions. Unfortunately, these schemes can themselves introduce distortion or other effects which are undesirable. As a simplified example, if a substantial duration of a signal is attenuated in order to prevent one brief peak thereof from exceeding a certain limit, the result may be an undesirable decrease in the signal-to-noise ratio of the signal.
It is an object of the present invention to set forth a technique for dynamically controlling the amplitude of an audio signal to prevent the peaks of the signal from exceeding predetermined limits while minimizing the distorting or undesirable effects of the amplitude control.